Electric furnace.



J. W. MOFFAT, mcmc'runm'ce; APPLICATION HLED 141.24.

Patehted Dec-19,1916.

W! TNE555.

zzvvs vraa reduction chamber which UNITED STATES PATENT OFFICE.

JAMES W. MOFFAT, OF TORONTO, ONTARIO, CANADA.

ELECTRIC FURNACE.

To aZl whom it may concern. Be it known that I, JAMES W. MOF'FAT, ot thecity of Toronto, in the county of York.

all arranged in fixed relationship to oneanother. Various troubles wereexperienced in tapping this furnace so as to satisfactorilv separate theslag and metal, and as an improvement the furnace described and claimedin United States Patent No. 1,108,924 of September 1, 1914 was devised oovercome the troubles experienced and successful. advantages,

the reduction chamber takes place owing to of making a tight jointbetween the two When the crucible is tilted.

also arrange tiltable together as a unit. I ore roasting in connectionwith the stack an device which will not only thoroughly dry the chargebut also preheat it and partially reduce it. Trouble is also experiencedwhen the ore and flux are showered same opening through which thefurnace gases escape owin to the fine particles be ing carried up withthe gases A further object of devise means for so leadin off the g andfeeding in the ore an losses from this cause are minimized. This objectI attain by leading off the flue gases from points adjacent the innerwall of the fines connect with a chamber forming part of the stack andby feeding in the ore through an opening sub- Specification of LettersPatent. Patten ted Dec, 19, 1916. Application filed larch 24 I ,1816.Scria1No.86,471.

stantially at the center of the top of the ,re-

uction chamber. I

y invention is hereinafter more specifically described and illustratedin the accompanying drawings in Which *igure 1 is a vertical Section ofthe furnace; Fig. 2 a side elevation partly in section; and Fig. 3 aplan view partly in section.

ferent figures.

1 is the reduction chamber of the furnace secured in fixed relationshipto the crucible l communicating therewith. The crucible is electricallyheated, 3 being the electrodes which are preferably six in number andare shown diagrammaticall 4 are tap holes or spouts, one at each side.These tap holes are of different sizes.

The crucible is supported in any suitable manner so that it may with thereduction chamber be tilted to facilitate the withdrawal of slag throughthe larger of the tap holes and the subsequent pouring of the moltencontents of the crucible through the smaller one.

ing shown preferably spindles 9 which are geared totrunnion Wheel 7.

shown for simultaneous operation.

e reduction chamber- 1 has its provided with openings for the exit theintroduction of the six openings 11 are proin the top for the passage ofgases.

ardizing of brick shapes. The hole 25 in the center is intended for theintroduction of the ore and flux. The ore thus falls through a centraldead space in which the gases are comparatively quiescent or may even becaused to eddy by suitably directing the air through the openings 22which are d to provide air for the combustion of any surplus reducinggas. The fine partipossible, four of the dues are led through the bottomof the furnace, the remaining two through one end of the chamber asshown. Between this chamber and the upright part 17 of the stack islocated a rotatable cylinder "18 suitable for the pre-heating of ores,this cylinder thus forn'iing' part of the stack. While a tube roaster ismentioned any other type of roaster suitable to the work may be used.

The hot furnace gases, when the furnace is in operation, pass into thechamber 16, thence over and through the charge passing through thecylinder 18 and up the stack, pro-heating and roasting the charge intheir passage. 19 of the ordinary type is providedfor the introductionof the charge of ore and flux into the rotatable cylinder. The ore,mixed with any necessary ux, is fed in through the top of the reductionchamber through a spout 20, the mouth of which is located below the endof the cylinder 18. This spout extends through the floor of thecombustion chamber, through the plate 13 and through the central hole inthe top 10 of the reduction chamber. When the reduction chamber andcrucible are to be tilted this spout must be raised out of the way. Anymeans may be provi for this pur ose. I show, however, a lever .21suitably ulcrumed to the floor 14 and to the spout. By operating thislever the spout can be raised clear of the to of the reduction chamberwhich is thus eft free to tilt.

23 are openings through which carbonaceous matter may be injected toproduce the reducing atmosphere necessary.

Reduction is carried out by showering the ore and flux in pulverulentcondition through the top of the reduction chamber down to the cruciblebelow. This charge having been pre-heatml and partially roasted isthoroughly dry and in such condition as to be readily reduced in thereducing atmosphere present in the reduction chamber. After a suliicientquantity of the reduced material has accumulated in the crucible thespent 20 is raised and the reduction chamber and crucible tilted to pouroff the slag and subsequently the metal as hereinbefore referred to.Owing to the fact that the reduc- Gl tion chamber and crucible tilttogether there the reduction is very little escape of heat from thecrucible, so that the furnace is in a condition for the immediateresumption of opcration as soon as it has been restored to its normalposition. The plate 13 may be made of suificient dimensions to close theopenings 11 when the furnace is tilted.

With this furnace a maximum of convenience in operation is secured. Theproper separation of the slag and the pouring of the metal til the righttime is insured, and owing to the [ire-heating of the charge theoperation of the furnace is very efficient and economical.

What I claim as my invention is l. A furnace comprising a stationarystack; and an unobstructed reduction cham ber and a crucible in fixedrelationship to one another and tiltable as a unit, the reductionchamber normally communicating with said stack.

2. A furnace comprising a stationary stack; and an unobstructedreduction chamber and a crucible in fixed relationship to one anotherand tiltable as a unit, the reduction chamber normally communicatingwith said stack and adapted when tilted to sub- 7 stantially close offthe stack.

3. A furnace comprising a stationary stack; an unobstructed reductionchamber and a crucible in fixed relationship to one another and tiltableas a unit, the reduction chamber havin a plurality of holes formed inits top; a p ate having openings therein adapted to register with theopenings in the top of the reduction chamber; and fines communicatingwith the openings in the said plate and with the stack.

4. A furnace comprising a stationary stack; an unobstructed reductionchamber and a crucible in fixed relationship to one another and tiltableas a unit, the reduction chamber having a plurality of holes formed inits top; a p ate having openings therein adapted to register with theopenings in the top of the reduction chamber and a charge hopper adaptedto feed through a central opening in the top of the reduction chamberwhen the latter is in normal position; and flues communicating with theother open ings in the said plate and with the stack.

5. A furnace comprising a stationary stack including charge pie-heatingmeans and a chamber for the reception of furnace gases through which thepreheating means discharges; and an unobstructed reduction chamber and acrucible in fixed relationship to one another and tiltable as a unit,the reduction chamber normally communicating with the chamber of saidstack.

6. A furnace comprising a stationary stack including charge pre-heatinmeans and a chamber for the reception 0 furnace gases through which thepro-heating discharges provided with an exit opening for the charge andan opening for the entrance of furnace gases; and an unobstructedreduction chamber and a crucible in fixed relationship to one anotherand tiltable as a unit, the reduction chamber being provided withopenings normally communicating with the aforesaid openings of thechamber of said stack.

7. A furnace comprising an unobstructed reduction chamber having a topprovided with a central hole for the introduction of the ore and aplurality of holes for the escape of furnace gases adjacent the wall ofthe chamber, means being provided for the introduction of air adjacentthe said Wall near the top and for the introduction of carbon near thebottom; a crucible below said reduction chamber in communicationtherewith; means for feeding ore and flux to said central hole; andmeans for conducting the furnace gases over the ore and flux before itis fed into the reduction chamber.

Signed at Toronto, Canada, this 9th day of arch, 1916, in the presenceof the two undersigned witnesses.

JAMES W. MOFFAT.

Witnesses E. P. HALL, N. R. TYNDALL.

